We are investigating the control of phenotypic expression of a set of highly regulated genes, those coding for eggshell proteins in silkmoths. Our long-term approach involves work at all levels of information flow, from structural organization and functional control of the genes, to maturation of mRNA, to protein synthesis, to transport and assembly of proteins into a supramolecular structure. Currently we are characterizing individual chorion encoding nucleic acid sequences, gaining insight into their evolution, timing of synthesis and arrangement of their genes within the chromosome.